Re: [Python-Dev] Python-Dev Digest, Vol 112, Issue 23
On 14/11/2012 09:58, Merlijn van Deen wrote:
On 14 November 2012 10:12, Chris Withers
wrote: ...which made me a little sad
Why did it make you sad? dict() takes 0.2?s, {} takes 0.04?s. In other words: you can run dict() _five million_ times per second, and {} twenty-five million times per second. That is 'a lot' and 'a lot'. It also means you are unlikely to notice the difference in real-world code. Just use the one you feel is clearer in the situation, and don't worry about micro-optimalization.
I'm inclined to agree, but it makes me sad for two reasons:
- it's something that people get hung up on, for better or worse. (if it wasn't, Doug wouldn't have written his article)
- it can make a difference, for example setting up a dict with many keys at the core of a type loop.
Without looking at implementation, they should logically perform the same...
Well, without looking at the implementation, you could form any opinion you
Chris Withers wrote: like about how they should perform. Still you could speculate that dict() will require a builtins name lookup, and that the process of passing keyword arguments might itself involve constructing a dictionary, so must inherently take at least a little longer than compiling a {} literal. Peter
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Peter Harris